Don't go chrome... this happens with Chrome
Black silicone will work wonders. Thats what i have on mine.
I'd recommend what I'm running, Mobil 1 75W140.
If you look on the drivers side top part of the differential at the front, right next to the yoke, you'll see the fill hole. Some will say use a pump, I had mine on a lift and dumped it in... 2 1/2 qts when I did it with a full tube of L/S additive.